Amotorboat travels 9 miles downstream (with the current) in 30 minutes. the return trip upstream (against the current) takes 90 minutes. which system of equations can be used to find x, the speed of the boat in miles per hour, and y, the speed of the current in miles per hour? recall the formula d = rt. 9 = 0.5(x – y) 9 = 1.5(x + y) 9 = 1.5(x – y) 9 = 0.5(x + y) 0.5 = 9(x – y) 1.5 = 9(x + y) 1.5 = 9(x – y) 0.5 = 9(x + y)

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to

Here are the 30 best lifetime baseball batting averages of all time, arranged in order from lowest to highest: 0.319, 0.329, 0.330, 0.331, 0.331, 0.333, 0.333, 0.333, 0.334, 0.334, 0.334, 0.336, 0.337, 0.338, 0.338, 0.338, 0.340, 0.340, 0.341, 0.341, 0.342, 0.342, 0.342, 0.344, 0.344, 0.345, 0.346, 0.349, 0.358, 0.366 if you were to build a histogram of these data, which of the following would be the best choice of classes?

The table below shows the number of free throw shots attempted and the number of shots made for the five starting players on the basketball team during practice. each player's goal is to make 80% of her shots.